1. Field of Invention
The present invention generally relates to the art of dewatering wet particulate matter, and more particularly to a method for increasing the rate of dewatering of sludge and fiber.
2. Background and Related Art
Industrial processes can produce wet solids that require dewatering before disposal or reuse. For example, sludge is produced during the biological treatment of wastewater. It is also produced through a variety of processes such as the manufacture of pulp and paper. The sludge is typically collected and treated with chemicals that promote flocculation of the sludge particles.
It is known to use thickeners such as polymers or lime as a chemical treatment for sludge. Hydrocarbon-based polymers such as cationic polyacrylamide (c-PAM) are commonly used. The flocculated sludge then is dewatered using various known dewatering devices, including, but not limited to, presses of various configurations, and centrifuges. The dewatered sludge is typically in the range of about 15-50% consistency (i.e. 85-50% water content).
The pressed cake of sludge then is disposed of through a variety of means, such as land filling, burning, or land spreading. It is apparent that the water contained in the dewatered sludge is a dead load, and it is therefore advantageous to reduce the water content of the final cake solids as much as possible.
Increasing the cake solids by even a relatively small amount reduces the amount of water associated with the sludge solids that makes disposal inefficient. Therefore, there is a need for a method for increasing the solids content of dewatered sludge.
Dewatering is also critical for processing fibers such as pulp. During papermaking the pulp is thickened through drainage or pressing during various process operations. Any improvement in the solids content of the drained pulp will improve throughput and increase production.
It is thus an intention of the present invention to provide a process, appropriate apparatus and method for dewatering wet particulate matter.